- From: Paul Groth <p.t.groth@vu.nl>
- Date: Tue, 06 Dec 2011 18:50:24 +0100
- To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- CC: "public-prov-wg@w3.org" <public-prov-wg@w3.org>
Hi Luc, Yes. I think that's what we wanted at least as a short cut. But can I do this?: Webpage: http://www.example.com/webpage entity(http://www.example.com/webpage, []) entity(http://www.example.com/webpage, [createdOn="June 4, 1998]) I think this is not allowed in the approach in the PROV-DM You would have to do: entity(http://www.example.com/webpage, []) entity(http://www.example.com/webpage/June41998, [createdOn="June 4, 1998]) wasComplementOf(http://www.example.com/webpage/June41998, http://www.example.com/webpage) This means in essence you do end up minting urls for provenance, right? Paul Luc Moreau wrote: > Hi Paul, > Yes, that's what the group wanted, I believe. > Luc > > On 12/06/2011 05:35 PM, Paul Groth wrote: >> Hi Luc, >> >> Hmm, I think I remember this now..... so everything can be an entity >> record as soon as you type it as such. >> >> For example if I have a webpage: >> >> http://www.example.com/webpage >> >> It becomes an entity record, as soon as I do: >> >> entity(http://www.example.com/webpage, []) >> >> Is that a correct interpretation? >> >> Paul >> >> >> >> >> Luc Moreau wrote: >>> Hi Paul, >>> >>> So, OK, we could mint identifiers for entity record >>> >>> entity(<a minted identifier here>, [ex:param="a", >>> ex:port="foo"]) >>> >>> (Which by the way is what OPM does.) >>> >>> How do you refer to the entity now? We don't know what this record is >>> about. >>> >>> Luc >>> >>> On 12/06/2011 05:11 PM, Paul Groth wrote: >>>> So I always thought that you could mint identifiers for entity records >>>> but you didn't have to and we supported that. >>>> >>>> But maybe that's my head inserting text where it shouldn't have >>>> been.... >>>> >>>> Paul >>>> >>>> Luc Moreau wrote: >>>>> ... the conclusion issue ;-) >>>>> >>>>> No, we have no formal decision on this. >>>>> >>>>> We wrote this in the prov-dm document a long time ago (before >>>>> fpwd), and >>>>> we have >>>>> been refining it over time. >>>>> >>>>> I think it's an inevitable consequence of two key decisions: >>>>> - distinguishing entities (in the world) from entity records (in the >>>>> provenance) >>>>> - not mandating the minting of new URIs for entity records >>>>> (no formal decision on this, but I think we have support for >>>>> it, since >>>>> we want to minimize the effort to generate provenance) >>>>> >>>>> Luc >>>>> >>>>> >>>>> On 12/06/2011 04:56 PM, Paul Groth wrote: >>>>>> Hi Luc, >>>>>> >>>>>> Do you have a pointer to wear we reached the consensus about the dual >>>>>> role of identifiers? >>>>>> >>>>>> Thanks, >>>>>> Paul >>>>>> >>>>>> Provenance Working Group Issue Tracker wrote: >>>>>>> PROV-ISSUE-183 (prov-dm-identifiers): identifiers in prov-dm >>>>>>> [prov-dm] >>>>>>> >>>>>>> http://www.w3.org/2011/prov/track/issues/183 >>>>>>> >>>>>>> Raised by: Luc Moreau On product: prov-dm >>>>>>> >>>>>>> >>>>>>> Hi, >>>>>>> >>>>>>> It think that it is now time to have a proper debate about >>>>>>> identifiers in prov-dm since comments are regularly expressed about >>>>>>> them. I have raised this issue about this topic so that we can track >>>>>>> the conversation properly. Our hope is to reach consensus on this >>>>>>> topic by the time of the third working draft. >>>>>>> >>>>>>> First, in the fpwd, there was a mention of "qualified identifier" >>>>>>> (appearing in a note see [1]). We have removed this term from the >>>>>>> second working draft. >>>>>>> >>>>>>> Second, the complementarity record now explicitly allows for linking >>>>>>> entity records across accounts. Its syntax allows for two >>>>>>> accounts to >>>>>>> be named. >>>>>>> >>>>>>> Third, identifiers for entities in prov-dm have a dual role [3]. An >>>>>>> entity has got an id (typically given by an application). An entity >>>>>>> record --- i.e. what we say about an entity in a provenance record >>>>>>> --- also has an id. There is a consensus that we shouldn't mint >>>>>>> identifiers for provenance records. Hence, the identifier of the >>>>>>> entity record is defined to be the same as the identifier of the >>>>>>> entity. >>>>>>> >>>>>>> The consequence of this is that two entity records in different >>>>>>> accounts may have the same identifier: they may say different things >>>>>>> about the same entity. For example, the document ex:doc was >>>>>>> generated by latex in account1, while in account 2, ex:doc is >>>>>>> described to be the result of a survey of a field by different >>>>>>> authors. >>>>>>> >>>>>>> This explains why we needed the complementarity record to name the >>>>>>> accounts as well. This assumes that account names need to be named >>>>>>> uniquely (see [4]). >>>>>>> >>>>>>> So, entity records identifiers are scoped to accounts. Note, I said >>>>>>> entity *records*, not entities. Hence, we are not breaking the >>>>>>> semantic web approach: an entity is a resource and is denoted by a >>>>>>> URI, and this remains true in all accounts. (I guess that from a >>>>>>> semantic web perspective we are not looking at a provenance >>>>>>> record as >>>>>>> resource, since we don't have a global URI to name it.) Finally, we >>>>>>> allow for accounts to be nested hierarchically; this fits nicely >>>>>>> with >>>>>>> abstraction in provenance records. Again, see [4]. >>>>>>> >>>>>>> Can you express your views about this approach, as currently defined >>>>>>> in the second draft of prov-dm? >>>>>>> >>>>>>> Thanks, Luc >>>>>>> >>>>>>> [1] >>>>>>> http://www.w3.org/TR/2011/WD-prov-dm-20111018/#expression-identifier >>>>>>> [2] >>>>>>> http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#record-complement-of >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> [3] >>>>>> http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#record-Entity >>>>>> >>>>>> >>>>>> >>>>>>> [4] >>>>>>> http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#record-Account >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> > -- Dr. Paul Groth (p.t.groth@vu.nl) http://www.few.vu.nl/~pgroth/ Assistant Professor Knowledge Representation & Reasoning Group Artificial Intelligence Section Department of Computer Science VU University Amsterdam
Received on Tuesday, 6 December 2011 17:51:06 UTC